Gear construction and arrangement



Jam 4, 1949. R. P. VAN ZANDT GEAR CONSTRUCTION AND ARRANGEMENT Filed April 16, 1947 INVENTOR.

AIYWKNEY Patented Jan. 4, 1949 UNITED SEARCH STATES PATENT OFFICE Rollin P. Van Zandt, Peoria, 111.. assignor to Caterpillar Tractor (30.. San Leandro, Calif, a

corporation of California Application April 16. 1947. Serial No. 741.818

2 Claims.

This invention relates to gears and particularly to the construction and arrangement of so-called cluster gears commonly used in gear type transmissions and the like.

like forms cut from a single piece of metal.

ception of a shaft.

on a splined shaft.

wear takes place.

than the other.

panying drawings.

In the drawings:

are also shown; and

Referring to the drawings in detail, the cluster gear of the present invention is illustrated as made of a small gear part l and a large gear part ll. Each of the two gear parts is formed The gear H has A cluster gear may comprise two or more gea 5 with a splined bore as best shown in Fig. 2 for The reception by a splined shaft l2 which in the prestwo gear forms are difierent pitch diameter but ent illustration may represent the driven shaft have a common axis and a single bore for reof a gear type transmission of conventional con- In transmissions the bore is struction. The gear parts l0 and H are interusually splined and fitted for sliding movement connected at their abutting faces by means pres- Sliding of the gear along ently to be described in a manner to cause them the shaft affects selective registration of its two to move together as they slide axially on the parts with other gears for varying the driving splined shaft l2. A driving gear l3 of large diratio through the transmission. Thus, the clusameter and a driving gear M of relatively smaller ter gear has a width and a bore length equal to diameter are formed integrally with a common two gears while only one of its gear parts is hub l5 and are driven by means not shown. By meshed at a time. The driving torque transmitsliding the cluster gear along the shaft I2, its ted through the gear is, therefore, always applied larger gear part II may be meshed with the to one end or the other with the result that the smaller driving gear M as shown in Fig. 1 or its gear tends to skew or cook on the shaft. Cocksmaller gear part Ill may be meshed with the ing of the gear results in misalignment of its larger driving gear l3 to vary the ratio of drive meshing teeth and unequal loading and excessive through the transmission, as is common practice. Gear shifting mechanism, not shown, is usually Another disadvantage of the conventional employed for imparting this sliding movement cluster gear is the diificulty encountered in manto the cluster gear and this shifting mechanism ufacture because one of its gear forms is smaller may include a fork, a part of which is illustrat- The gear teeth on the smaller ed at IS in Fig. 1, received in an annular groove part terminate adjacent the wall or shoulder H in the cluster gear to move the gear axially formed by the larger part and must, therefore. along the shaft without interfering with its robe cut by a shaping cutter method rather than tation. the faster and more efficient method of hobbing. Because of necessity of the cluster ear sliding An object of the present invention is to provide freely on the splined shaft l2, there is considera construction and arrangement for cluster gears able tolerance or play in the splined connection to overcome the above disadvantages and to form and when the gears are rotating there is a tendsuch a gear in two separable parts connected by ency for the driving gear to cock the cluster gear relative rotation but locked against separation relatiye to the splined shaft. Thus, the driving in an axial direction. A further object is to proforceiis unbalanced or unequally distributed and vide a cluster gear in which driving torque apthe engagement between the teeth of the driving plied to either of its gear parts is transmitted gear and the driven cluster gear is not continuthrough that part only so that balanced loading ous throughout the full length of the tooth, as is between the driving connection of the gear and desirable. This effects uneven wear of the teeth the shaft upon which it is mounted is maintained. of both gears and results in rapid deterioration Still further objects and advantages of the invenand unsatisfactory operation. tion are made apparent in the following specifi- According to the present invention, the two cation wherein reference is made to the accomgear parts l0 and II of the cluster gear are formed as separate gears rather than integrally as a single part in the conventional manner. Fig. 1 is a central vertical sectional view of a The separate gears Ill and II are adapted to be cluster gear arrangement embodying the presconnected together at their abutting faces by ent invention and illustrated in the environment means best illustrated in Fig. 2. The gear part of a transmission, fragmentary parts of which H] is shown as provided with an undercut groove l8 to form a radially inwardly projecting flange Fig. 2 is an isometric View of the two parts of cut away in three parts to provide three radially the cluster gear in separated relation illustrating inwardly projecting lugs I9.-

connecting means on both parts.

on its abutting face, and adjacent its centrally splined bore, spaced axial projections 20, each provided with a radially outwardly projecting lug 2|. The lugs 2| correspond in number and position with the lugs IS on the gear l and also correspond in number and spacing with the spaces between the lugs I9 on the gear I0. Consequently, in bringing the gears l0 and H together in face to face relationship, the lugs 2| will enter the undercut groove l8 in the gear I 0 through the spaces between the lugs 19. Then upon partial relative rotation of the gear parts In and II, the lugs 2| will be disposed behind the lugs l9 and endwise or axial separation of the gears is prevented. Three sets of interengaging lugs l9 and 2| are shown but any desired number of such lugs may, of course, be employed.

The gears 10 and II assembled in this manner provide a cluster gear that may be slipped onto the splined shaft l2 and because of the splined connection between each gear part and the shaft, their rotation on the shaft and therefore their rotation with relation to each other is prevented. Consequently, it is impossible for the gear parts 10 and I I to be separated from each other axially after they have been locked together and mounted on a shaft. Each gear part is, however, capable of independent rotation to the extent permitted by the tolerance in its splined connection with the shaft. Thus, when the driving gear ll of Fig. 1 is driving the gear part H, the gear part Ill is not rigidly fixed to the part II and the load transmitted from the gear 14 to the gear II is centered or balanced and does not tend to cock the cluster gear with relation to the shaft. The same condition prevails in the other gear position when the driving gear I3 meshes with the cluster gear part H) as at this time the cluster gear part II is free and is not affected by forces transmitted through the gear III to the splined 4 shaft l2. Because of the construction illustrated. the separate gears l0 and II which make up the cluster gear may be formed by the simplest gear cutting operation and are, therefore, less costly and simpler to manufacture than conventional types of cluster gears.

Iclaim:

1. A cluster gear adapted to be mounted on a splined shaft comprising, separate gear parts having splined bores for reception of the shaft, and means for connecting said gear parts together including lugs on each gear part interengageable upon relative rotation of the parts to secure them against axial separation whereb the splined connection of the parts on the shaft will prevent their separation.

2. A cluster gear comprising two gear like parts having interengageable lugs adapted to connect the parts for relative rotation but to prevent axial separation thereof, said lugs being engageable and disengageable by relative rotation of the gear parts, and splined bores in the parts for assembly on a splined shaft to cause them to rotate with the shaft and to lock them against relative rotation after they are assembled.

ROLLIN P. VAN ZANDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 871,677 Dawes Nov. 19, 1907 1,724,822 Brown Aug. 13, 1929 1,943,266 Condron Jan. 9, 1934 1,993,729 Brouwer Mar. 12, 1935 1,731,151 Royce Oct. 8, 1929 

